Use of the metal artefact reduction tool in the identification of fractured endodontic instruments in cone-beam computed tomography.

AIM: To evaluate the influence of the metal artefact reduction (MAR) tool in the diagnosis of fractured instruments in root canals of extracted mandibular molars, with or without root canal fillings. METHODOLOGY: The root canals of 31 mandibular molars were divided into four groups: (i) the control group, without root fillings; (ii) the fracture group, without fillings and with fractured files; (iii) the fill group, with root filling; and (iv) the fill/fracture group, root filled and with fractured files. The following instruments were used as fractured endodontic instruments: stainless steel hand files, NiTi reciprocating files and NiTi rotary files. Each tooth was inserted in a dry mandible to obtain cone-beam computed tomography (CBCT) images using a CBCT OP300 3D Maxio (Instrumentarium Dental, Tuusula, Finland) and Picasso Trio (Vatech, Hwaseong, Republic of Korea), with and without application of the MAR tool. All images were evaluated by three radiologists for the presence or absence of fractured files on a 5-point scale. The diagnostic accuracy (area under ROC curve) was calculated. Image noise was measured in regions of trabecular and cortical bone and soft tissue. The comparison between the ROC curve values with the MAR tool enabled or disabled was performed using a t-test. A t-test was also employed for comparing image noise when the MAR tool was enabled and disabled. The significance level was set at 5%. RESULTS: The use of the MAR tool did not influence the diagnostic accuracy for identifying fractured endodontic instruments in root canals with and without fillings in both CBCT systems (P > 0.05), nor did it influence the image noise (P > 0.05). CONCLUSIONS: The MAR tool on these two devices did not increase the detection of fractured endodontic instruments and did not reduce image noise using extracted mandibular molars. Therefore, the MAR tool is not recommended for evaluation of fractured endodontic instruments in teeth with and without root fillings in mandibular molars.

The CODATwins Project: The Current Status and Recent Findings of COllaborative Project of Development of Anthropometrical Measures in Twins.

The COllaborative project of Development of Anthropometrical measures in Twins (CODATwins) project is a large international collaborative effort to analyze individual-level phenotype data from twins in multiple cohorts from different environments. The main objective is to study factors that modify genetic and environmental variation of height, body mass index (BMI, kg/m2) and size at birth, and additionally to address other research questions such as long-term consequences of birth size. The project started in 2013 and is open to all twin projects in the world having height and weight measures on twins with information on zygosity. Thus far, 54 twin projects from 24 countries have provided individual-level data. The CODATwins database includes 489,981 twin individuals (228,635 complete twin pairs). Since many twin cohorts have collected longitudinal data, there is a total of 1,049,785 height and weight observations. For many cohorts, we also have information on birth weight and length, own smoking behavior and own or parental education. We found that the heritability estimates of height and BMI systematically changed from infancy to old age. Remarkably, only minor differences in the heritability estimates were found across cultural-geographic regions, measurement time and birth cohort for height and BMI. In addition to genetic epidemiological studies, we looked at associations of height and BMI with education, birth weight and smoking status. Within-family analyses examined differences within same-sex and opposite-sex dizygotic twins in birth size and later development. The CODATwins project demonstrates the feasibility and value of international collaboration to address gene-by-exposure interactions that require large sample sizes and address the effects of different exposures across time, geographical regions and socioeconomic status.

Effects of the detailed protein composition of milk on curd yield and composition measured by model micro-cheese curd making of individual milk samples.

The effect of the contents of casein (CN) and whey protein fractions on curd yield (CY) and composition was estimated using 964 individual milk samples. Contents of αS1-CN, αS2-CN, ß-CN, γ-CN, glycosylated κ-CN (Gκ-CN), unglycosylated κ-CN, ß-LG, and α-LA of individual milk samples were measured using reversed-phase HPLC. Curd yield and curd composition were measured by model micro-cheese curd making using 25 mL of milk. Dry matter CY (DMCY) was positively associated with all casein fractions but especially with αS1-CN and ß-CN. Curd moisture decreased at increasing ß-CN content and increased at increasing γ-CN and Gκ-CN content. Due to their associations with moisture, Gκ-CN and ß-CN were the fractions with the greatest effect on raw CY, which decreased by 0.66% per 1-standard deviation (SD) increase in the content of ß-CN and increased by 0.62% per 1-SD increase in the content of Gκ-CN. The effects due to variation in percentages of the casein fractions in total casein were less marked than those exerted by contents. A 1-SD increase in ß-CN percentage in casein (+3.8% in casein) exerted a slightly negative effect on DMCY (ß = -0.05%). Conversely, increasing amounts of αS1-CN percentage were associated with a small increase in DMCY. Hence, results suggest that, at constant casein and whey protein contents in milk, the DMCY depends to a limited extent on the variation in the αS1-CN:ß-CN ratio. κ-Casein percentage did not affect DMCY, indicating that the positive relationship detected between the content of κ-CN and DMCY can be attributed to the increase in total casein resulting from the increased amount of κ-CN and not to variation in κ-CN relative content. However, milk with increased Gκ-CN percentage in κ-CN also shows increased raw CY and produces curds with increased moisture content. Curd yield increased at increasing content and relative proportion of ß-LG in whey protein, but this is attributable to an improved capacity of the curd to retain water. Results obtained in this study support the hypothesis that, besides variation in total casein and whey protein contents, variation in protein composition might affect the cheese-making ability of milk, but this requires further studies.

Diagnosis of external root resorption in teeth close and distant to zirconium implants: influence of acquisition parameters and artefacts produced during cone beam computed tomography.

AIM: To assess the influence of artefacts, the metal artefact reduction (MAR) tool and kilovoltage (kVp) on the diagnosis of simulated external root resorption (ERR) in teeth close and distant to zirconium implants in cone beam computed tomography (CBCT) images. METHODOLOGY: Cavities (0.62 mm in diameter and 0.19 mm deep) were created in the apical thirds of 12 roots on the buccal, lingual, distal or mesial surface; ten roots served as controls. The roots were randomly positioned in the first and second right and left premolar sockets of a dry human mandible, and a zirconium implant was placed in the socket of the first right molar. A ProMax 3D unit varying kVp (70, 80, or 90 kVp) and with the MAR tool activated or not was used to obtain CBCT scans. Five examiners evaluated all images to determine the area under the receiver operating characteristic (ROC) curve, sensitivity and specificity. RESULTS: The ROC values and sensitivity were not affected by MAR or artefacts regardless of the distance to the implant (P > 0.05), whilst increasing kVp from 70 to 90 led to a significant increase in these values (P = 0.0202 and 0.0199, respectively). Specificity was not affected by the factors studied (P > 0.05). CONCLUSIONS: Amongst the factors studied, only kVp influenced the diagnosis of simulated external root resorption in CBCT images. Increasing kVp from 70 to 90 improved the accuracy in diagnosing the simulated lesions.

Root canal configuration and its relation with endodontic technical errors in premolar teeth: a CBCT analysis.

AIM: To evaluate the association between endodontic technical errors and the root canal configuration (RCC) of human premolars, as well as their relationship with periapical lesions through cone-beam computed tomography (CBCT) images. METHODOLOGY: The sample consisted of CBCT scans belonging to 136 patients, totalling 152 root filled premolars (185 roots). CBCT images were evaluated by two oral radiologists. RCC was recorded according to Vertucci's classification, and the endodontic treatment quality was judged on the presence and type of technical endodontic errors (underfilling, overfilling, nonhomogeneous filling, nonfilled canal, fractured instruments, root deviation and absence of coronal restoration). In addition, the presence of periapical lesions associated with each RCC was recorded. Data were expressed by frequencies and percentages, and intraobserver agreement was calculated using the Kappa test. RESULTS: The most common RCC was type I (71%), followed by type IV (15%), type II (8%), type V (3%), type VI (1%) and type III (1%). Types VII and VIII were not observed in the sample. Underfilling was the most frequent endodontic technical error for most RCCs, except for types IV, V and 'other', whose most frequent error was a nonfilled canal. The presence of technical errors was greater with an increase in the proportion of the periapical lesions. The intraobserver agreement was excellent. CONCLUSIONS: There was an increase in the prevalence of endodontic technical errors and in the presence of periapical lesions as the anatomical complexity of the root canals increased. Underfilled and nonfilled canal were the most frequent endodontic technical errors.

Spermatogonial behavior in marmoset: a new generation, their kinetics and niche.

STUDY QUESTION: Could a more detailed evaluation of marmoset spermatogonial morphology, kinetics and niches using high-resolution light microscopy (HRLM) lead to new findings? SUMMARY ANSWER: Three subtypes of marmoset undifferentiated spermatogonia, which were not evenly distributed in terms of number and position along the basal membrane, and an extra premeiotic cell division not present in humans were identified using HRLM. WHAT IS KNOWN ALREADY: The seminiferous epithelium cycle (SEC) of marmosets is divided into nine stages when based on the acrosome system, and several spermatogenic stages can usually be recognized within the same tubular cross-section. Three spermatogonial generations have been previously described in marmosets: types Adark, Apale and B spermatogonia. STUDY DESIGN, SIZE, DURATION: Testes from five adult Callithrix penicillata were fixed by glutaraldehyde perfusion via the cardiac route and embedded in Araldite plastic resin for HRLM evaluation. Semi-thin sections (1 µm) were analyzed morphologically and morphometrically to evaluate spermatogonial morphology and kinetics (number, mitosis and apoptosis), spermatogenesis efficiency and the spermatogonial niche. PARTICIPANTS/MATERIALS, SETTING, METHODS: Shape and nuclear diameter, the presence and distribution of heterochromatin, the granularity of the euchromatin, as well as the number, morphology and degree of nucleolar compaction were observed for morphological characterization. Kinetics analyses were performed for all spermatogonial subtypes and preleptotene spermatocytes, and their mitosis and apoptosis indexes determined across all SEC stages. Spermatogenesis parameters (mitotic, meiotic, Sertoli cell workload and general spermatogenesis efficiency) were determined through the counting of Adark and Apale spermatogonia, preleptotene and pachytene primary spermatocytes, round spermatids, and Sertoli cells at stage IV of the SEC. MAIN RESULTS AND THE ROLE OF CHANCE: This is the first time that a study in marmosets demonstrates: the existence of a new spermatogonial generation (B2); the presence of two subtypes of Adark spermatogonia with (AdVac) and without (AdNoVac) nuclear rarefaction zones; the peculiar behavior of AdVac spermatogonia across the stages of the SEC, suggesting that they are quiescent stem spermatogonia; and that AdVac spermatogonia are located close to areas in which blood vessels, Leydig cells and macrophages are concentrated, suggesting a niche area for these cells. LARGE SCALE DATA: Not applicable. LIMITATIONS, REASONS FOR CAUTION: The C. penicillata spermatogonial kinetics evaluated here consider spermatogonial number across the SEC and their mitotic and apoptotic figures identified in HRLM sections. Therefore, caution is required when comparing absolute values between species. Although morphometric evaluation has suggested that AdVac spermatogonia are stem cells, a functional proof of this is still missing. It is known that parameters of the spermatogenic process in C. penicillata have similarities with those of the common marmoset C. jacchus, however, a detailed study of spermatogonial morphology, kinetics and niche has not yet been performed in C. jacchus, and a full comparison of the two species is not possible. WIDER IMPLICATIONS OF THE FINDINGS: Our findings in C. penicillata contribute to a better understanding of the spermatogonial behavior and spermatogenesis efficiency in non-human primates. Given the phylogenetic closeness of the marmoset to the human species, similar processes might occur in humans. Therefore, marmosets may be an excellent model for studies regarding human testicular biology, fertility and related disorders. STUDY FUNDING/COMPETING INTEREST(S): Experiments were partially supported by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG) and Conselho Nacional de Desenvolvimento Cientifico e Tecnológico (CNPq). The authors declare that there are no conflicts of interest.

Correlation between in vitro and in vivo data on food digestion. What can we predict with static in vitro digestion models?

During the last decade, there has been a growing interest in understanding food's digestive fate in order to strengthen the possible effects of food on human health. Ideally, food digestion should be studied in vivo on humans but this is not always ethically and financially possible. Therefore, simple in vitro digestion models mimicking the gastrointestinal tract have been proposed as alternatives to in vivo experiments. Thus, it is no surprise that these models are increasingly used by the scientific community, although their various limitations to fully mirror the complexity of the digestive tract. Therefore, the objective of this article was to call upon the collective experiences of scientists involved in Infogest (an international network on food digestion) to review and reflect on the applications of in vitro digestion models, the parameters assessed in such studies and the physiological relevance of the data generated when compared to in vivo data. The authors provide a comprehensive review in vitro and in vivo digestion studies investigating the digestion of macronutrients (i.e., proteins, lipids, and carbohydrates) as well as studies of the bioaccessibility and bioavailability of micronutrients and phytochemicals. The main conclusion is that evidences show that despite the simplicity of in vitro models they are often very useful in predicting outcomes of the digestion in vivo. However, this has relies on the complexity of in vitro models and their tuning toward answering specific questions related to human digestion physiology, which leaves a vast room for future studies and improvements.

Skeletal maturation, fundamental motor skills, and motor performance in preschool children.

Relationships among skeletal age (SA), body size and fundamental motor skills (FMS) and motor performance were considered in 155 boys and 159 girls 3-6 years of age. Stature and body mass were measured. SA of the hand-wrist was assessed with the Tanner-Whitehouse II 20 bone method. The Test of Gross Motor Development, 2nd edition (TGMD-2), and the Preschool Test Battery were used, respectively, to assess FMS and motor performance. Based on hierarchical regression analyses, the standardized residuals of SA on chronological age (SAsr) explained a maximum of 6.1% of the variance in FMS and motor performance in boys (ΔR2 3 , range 0.0%-6.1%) and a maximum of 20.4% of the variance in girls (ΔR2 3 , range 0.0%-20.4%) over that explained by body size and interactions of SAsr with body size (step 3). The interactions of the SAsr and stature and body mass (step 2) explained a maximum of 28.3% of the variance in boys (ΔR2 2 , range 0.5%-28.3%) and 16.7% of the variance in girls (ΔR2 2 , range 0.7%-16.7%) over that explained by body size alone. With the exception of balance, relationships among SAsr and FMS or motor performance differed between boys and girls. Overall, SA per se or interacting with body size had a relatively small influence in FMS and motor performance in children 3-6 years of age.

Prevalence of soft tissue calcifications in the maxillofacial region detected by cone beam CT.

OBJECTIVE: To determine the prevalence of soft tissue calcifications in cone beam computed tomography (CBCT) scans with different fields of view (FOV) and to assess its relation with the clinical relevance of the CBCT findings. MATERIAL AND METHODS: One thousand CBCT scans were grouped according to FOV's size and region scanned (MX-FOV, maxilla; MD-FOV, mandible; and MM-FOV, maxilla/mandible) and evaluated for the presence of soft tissue calcifications. Laterality and length of the elongated styloid processes (ESP) were also assessed. RESULTS: Eight hundred and eighty-two soft tissue calcifications were detected in 626 (62.6%) patients. MM-FOV presented the highest prevalence (76.8%), followed by MD-FOV (60.6%) and MX-FOV (57.2%). ESP and tonsillolith were the most frequent calcifications. Calcifications requiring treatment or not and those in need of follow-up accounted for 6.9%, 92.7%, and 0.3% of cases, respectively. There was no association between calcifications and subjects' gender or age (p > .05). Most cases of ESP occurred bilaterally and were longer in males (p < .05). CONCLUSIONS: There is a high prevalence of soft tissue calcifications in CBCT, and ESP and tonsilloliths are the most common types in all evaluated FOVs. While most cases do not require treatment, we emphasize the importance of detailed CBCT assessment for its diagnosis.

Voriconazole-induced periostitis deformans: serial imaging in a patient with ANCA vasculitis.

OBJECTIVES: A 61-year-old with acute granulomatosis and polyangiitis developed Aspergillus fumigatus pneumonia after admission to the intensive care unit with a small bowel perforation. This occurred after immunosuppression (intravenous methylprednisolone, intravenous cyclophosphamide, and plasmapheresis) for his initial presentation with stage 3 acute kidney injury. MATERIALS AND METHODS: The mycologist recommended long-term treatment with voriconazole after initial recovery. RESULTS: After 7 months of treatment, the patient complained of joint pain and swelling in his hands. Radiographs, computed tomography, and single-photon emission computed tomography appearances were consistent with periostitis. A diagnosis of Voriconazole-induced periostitis deformans was made and the voriconazole was stopped. Plasma fluoride level was 278 µg/L (normal range < 50 µg/L). Discontinuation of voriconazole led to clinical improvement. CONCLUSIONS: Periostitis deformans due to fluorosis is a rare complication of voriconazole treatment. The imaging in our case is unusually dramatic. We were able to track the evolution of periosteal reactions over serial imaging.

Correction to: Voriconazole-induced periostitis deformans: serial imaging in a patient with ANCA vasculitis.

The original version of this paper unfortunately contained mistakes in the affiliations for all authors.

Pre-transplant histology does not improve prediction of 5-year kidney allograft outcomes above and beyond clinical parameters.

Pre-implant kidney biopsy is used to determine suitability of marginal donor kidneys for transplantation. However, there is limited data examining the utility of pre-implant histology in predicting medium term graft outcome. This retrospective study examined kidney transplants over a 10-year period at a single center to determine if pre-implant histology can identify cases of eGFR ≤35 ml/min/1.73m2 at 5 year follow up beyond a clinical predictive logistic regression model. We also compared outcomes of dual kidney transplants with standard single kidney transplants. Of 1195 transplants, 171 received a pre-implant kidney biopsy and 15 were dual transplants. There was no significant difference in graft and patient survival rates. Median eGFR was lower in recipients of biopsied kidneys compared with standard kidney transplants (44 vs. 54 ml/min/1.73m2, p < .001). Median eGFR of dual transplant and standard kidney transplants were similar (58 vs. 54 ml/min/1.73m2, p = .64). Glomerular sclerosis (p = .05) and Karpinski Score (p = .03) were significant predictors of eGFR at 5-years in multivariate analysis but did not improve discrimination of eGFR ≤35 ml/min/1.73m2 at 5-years beyond a clinical prediction model comprising donor age, donor hypertension and terminal donor creatinine (C-statistic 0.67 vs. 0.66; p = .647). Pre-implant histology did not improve prediction of medium-term graft outcomes beyond clinical predictors alone. Allograft function of dual transplant kidneys was similar to standard transplants, suggesting that there is scope to increase utilization of kidneys considered marginal based on histology.

Respiratory syncytial virus induces phosphorylation of mTOR at ser2448 in CD8 T cells from nasal washes of infected infants.

Respiratory syncytial virus (RSV)-specific CD8(+) T cell responses do not protect against reinfection. Activation of mammalian target of rapamycin (mTOR) impairs memory CD8(+) T cell differentiation. Our hypothesis was that RSV inhibits the formation of CD8(+) T cells memory responses through mTOR activation. To explore this, human and mouse T cells were used. RSV induced mTOR phosphorylation at Ser2448 in CD8 T cells. mTOR activation by RSV was completely inhibited using rapamycin. RSV-infected children presented higher mTOR gene expression on nasal washes comparing to children infected with metapneumovirus and rhinovirus. In addition, RSV-infected infants presented a higher frequency of CD8(+) pmTORser2448(+) T cells in nasal washes compared to RSV-negative infants. Rapamycin treatment increased the frequency of mouse CD8 RSV-M282-90 pentamer-positive T cells and the frequency of RSV-specific memory T cells precursors. These data demonstrate that RSV is activating mTOR directly in CD8 T cells, indicating a role for mTOR during the course of RSV infection.

Effect of delayed scanning on imaging and on the diagnostic accuracy of vertical root fractures in two photostimulable phosphor plates digital systems.

AIM: To evaluate the influence of delayed scanning on images obtained with two PSPs digital systems and on the diagnostic accuracy of vertical root fracture (VRF) by means of objective and subjective analyses. METHODOLOGY: Forty single-rooted human teeth were divided into two groups, one without VRFs and another with VRFs induced by a universal testing machine. Two digital systems (VistaScan(®) and Express(®) ) were used to radiograph all teeth, and the resulting plates were scanned at four time-points: T0-immediately, T1-30 min, T2-2 h and T3-4 h after exposure. An aluminium (Al) wedge was used to evaluate the change in mean grey values as each scan was delayed. Three observers screened all images for VRFs, and one-fourth of the sample was revaluated after thirty days. Areas under the receiver operating characteristic (ROC) curve, sensitivity, specificity and accuracy values were compared by anova. RESULTS: Intra- and interobserver agreement ranged from moderate to substantial and fair to moderate, respectively. There was no significant difference amongst scan delays with regard to sensitivity, specificity and accuracy; however, there were significant differences in the area under the ROC curve, with the 4-h delayed scan being associated with lower values compared to the others (P = 0.019). As for objective analysis, there was a significant difference amongst all different scanning time-points for the two systems (P = 0.001), except between the 30-min and 2-h delayed scans in the VistaScan(®) system. CONCLUSION: Whilst delayed scanning caused changes to the density of images acquired with the systems studied, it did not seem to interfere with VRF diagnosis except when scanning was delayed for 4 h, which should therefore be avoided.

Digital radiographs displayed on different devices: effect on the detection of vertical root fractures.

AIM: To evaluate whether the type of display device affects the detection of vertical root fractures (VRFs) on digital radiographs in unfilled canals and canals with fibreglass posts. METHODOLOGY: Forty single-rooted human teeth were decoronated, and the root canals were prepared. The teeth were divided into 2 groups: controls (20 teeth) and with VRF (20 teeth). The VRFs were induced using an universal testing machine. Periapical radiographs of all teeth, with canal unfilled or with a fibreglass post, were obtained using the parallel technique in 3 directions (ortho-, mesio- and distoradial) on storage phosphor plates (VistaScan®). All images were evaluated and re-evaluated after 30 days by 3 examiners on a 5-point scale using 4 different devices (notebook display with full high definition resolution, desktop display with a standard resolution, 8-inch Android(™) tablet with high definition resolution and a 9.7-inch iPad® tablet with Retina resolution). Areas under ROC curves, sensitivity, specificity and accuracy values were compared by anova. RESULTS: The weighted kappa values for intra- and interobserver reproducibility were 0.55-0.88 and 0.31-0.65, respectively. There was a significant difference (P < 0.05) in relation to the area under the ROC curve, specificity and sensitivity when unfilled canals were compared with canals with a fibreglass post; however, no difference was observed for the different devices studied. CONCLUSIONS: The type of display device did not affect the detection of VRFs. Thus, the detection of VRFs can be performed using different screen sizes and resolutions.

Ability of HMGB1 protein to bind to intrinsically bent and non-bent DNA sites in the AMPD2 gene amplicon.

HMGB-like proteins are architectural chromatin factors, and their function is heavily dependent on their ability to interact with DNA (especially non-canonical DNA structures). HMGB1 is involved in many DNA processes, and dysregulation of HMGB protein expression has profound effects on cellular transcription, resulting in severe developmental defects as well as cancer. During DNA replication, elements that form the origin are still not well defined in metazoans. Sites with A (adenine) or T (thymine) repeats cause intrinsic curvatures in the DNA and are described to be involved in the replication machinery by providing binding sites to replication proteins. As a result, the DNA molecule shows intrinsically bent DNA sites, caused by periodic repeats of 2 or more As/Ts (dA/dT) as well as intrinsically non-bent DNA sites (INBDs), due to a succession of curvatures that cancel each other. In the present study, we mapped 11 INBDSs present in the AMPD2 gene that are related to each replication origin (oriGNAI3, oriC, oriB, and oriA). Following characterization of INBDSs, we tested the ability of HMGB1 to bind to the bent (b1, b2, b4a, b4b, b5, b6, b7, and b8) and non-bent DNA fragments (nb7, nb11, nb1, nb2, nb4, and nb5) via electrophoretic mobility shift assays. All fragments showed efficient binding to HMGB1. However, the non-bent DNA fragments nb2, nb4, and nb5 showed slightly reduced binding efficiency.

Comparative petiole anatomy of cassava (Manihot) species.

In this study, we describe the petiole anatomy of six wild cassava (Manihot) species, one hybrid, and two cultivars of Manihot esculenta, in order to identify their dominant anatomical patterns and relate them to possible adaptations to abiotic factors in the Cerrado biome. The median parts of several petiole samples were transversally and longitudinally sectioned and stained. The results include data for the taxonomic classification of the genus, including distinctive anatomical characteristics of hybrid varieties of cassava and wild species, such as the presence/absence of trichomes and a hypodermis, layer type and number in the cortex, number of vascular bundles, cell types in the pith, and type of organization. Morphological analysis revealed differences in length and shape of the petiole insertion. The presence of trichomes, a hypodermis, the amount and type of supporting tissue in the cortex, as well as gelatinous fibers, may be related to drought tolerance.

Short communication: Latin-style fresh cheese enhances lactic acid bacteria survival but not Listeria monocytogenes resistance under in vitro simulated gastrointestinal conditions.

Different studies in humans have provided evidence about the health benefits of probiotics. However, most probiotic strains do not maintain good viability in the harsh conditions of the gastrointestinal tract (GIT). In the present study, Latin-style fresh cheese produced with potential probiotic bacteria was tested to evaluate this cheese type as a food carrier for the delivery of viable microorganisms after exposure to simulated GIT conditions. The resistance of 28 lactic acid bacteria (LAB) strains and Listeria monocytogenes upon exposure to acidic conditions (pH 2.5) and bile and pancreatic enzymes (0.3% of bile salts and 0.1% of pancreatin) was evaluated in vitro. When compared with fresh cultures, fresh cheese greatly improved LAB survival to simulated GIT conditions, as no loss of viability was observed in either acidic conditions (pH 2.5) or bile salts and pancreatin environment over a 3-h period. In opposition, L. monocytogenes did not survive after 1h under acidic conditions. These data demonstrated that Latin-style fresh cheese could play an important role in probiotic protection against gastrointestinal juices, enhancing delivery within the gut and thereby maximizing potential health benefits of LAB.